BBY 464 Semantic Information Management (Spring 2016) Semantic Web Yaşar Tonta & Orçun Madran [yasartonta, Hacettepe University Department of Information Management
Knowledge representation XML: lets everyone create their own tags RDF: expresses meaning using triples (subject, verb, and object) – “Orçun teaches BBY464.” – Uses URIs to describe them: – Subject: – Object: – Verbs (“teach”) are identified by URIs as well
RDF example with URIs and RDF/XML
Ontologies RDFS: Resource Description Framework Schema OWL: Web Ontology Language
Shallow ontologies
Deep ontologies
Agents “bots” (to find tickets, hotels, etc.) “shared meaning”
Expressing Meaning Date – February 16, 2016 – 16 February 2016 – 16/02/2016 – 02/16/2016 – What about “03/03/2016” – … Shoe sizes
Source: Madnick & Zhu, 2006, p. 462, 466 Data quality and interpretation Semantic differences Interpretation problems (metric system, “year” - last 12 months, calendar year, financial year…)
Meaning Metaphors Thought cannot exist without metaphors. Susan Sontag “Tartışma Savaştır İddialarınız savunulamaz. Argümanımdaki her zayıf fikre saldırdı. Eleştirileri doğrudan hedefi buldu. Argümanını yerle bir ettim. Onunla asla bir tartışmada galip gelemedim. Kabul etmiyor musun? O zaman, ateş! Bu stratejiyi kullanırsan o seni bitirecek. Argümanlarımın hepsini tahrip etti.” -G. Lakoff ve M. Johnson, Metaforlar: Hayat, Anlam ve Dil. İstanbul: İthaki. S. 28. Disambiguity – “Visiting relatives can be a nuisance”
Seks metaforları (ABD)
Logic Rules and inference – “This sentence is false” RIF: Rule Interchange Format
Proof Validation
Semantic Web – Layered Architecture